diff --git a/CMakePresets.json b/CMakePresets.json
index dbce447..42c09a5 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -1,6 +1,6 @@
 {
   "version": 3,
-  "cmakeMinimumRequired": {"major": 3, "minor": 14, "patch": 0},
+  "cmakeMinimumRequired": {"major": 3, "minor": 21, "patch": 0},
   "configurePresets": [
     {
       "name": "gcc",
diff --git a/docs/BUILDING.md b/docs/BUILDING.md
index c1aabf0..fbfc9b5 100644
--- a/docs/BUILDING.md
+++ b/docs/BUILDING.md
@@ -6,7 +6,7 @@ Build setup, dependencies, and how to run tests. For project overview, see the [
 
 ## Requirements
 
-- **CMake** — **3.14 or newer** if you use **`cmake --preset`** ([CMakePresets.json](../CMakePresets.json)). The root [CMakeLists.txt](../CMakeLists.txt) declares `cmake_minimum_required(3.14)` for manual configures; presets are the documented workflow.
+- **CMake** — **3.21 or newer** if you use **`cmake --preset`** ([CMakePresets.json](../CMakePresets.json)) — presets format v3 requires CMake 3.21. The root [CMakeLists.txt](../CMakeLists.txt) declares `cmake_minimum_required(3.14)` for manual configures; presets are the documented workflow.
 - **Compiler** — **C++20** required (use a C++20-capable GCC or Clang).
 - **GoogleTest & GoogleMock** — Install development packages for your OS (below). The build also uses **FetchContent** to obtain GoogleTest when you configure with CMake.
 - **Threads** — For concurrency tests (and deadlock tests when enabled).
@@ -83,7 +83,7 @@ brew install googletest cmake ninja
 ## Tools and environment
 
 - **Compiler:** C++20-capable **GCC** or **Clang**
-- **Build:** CMake **3.14+** for presets; Ninja recommended (generator in presets)
+- **Build:** CMake **3.21+** for presets (format v3); Ninja recommended (generator in presets)
 - **Tests:** GoogleTest & GoogleMock
 - **IDE:** Cursor (optional Socratic rules in `.cursor/rules/`)